Apical periodontitis: etiology, pathogenesis, classification

CLASSIFICATION 
 
The type of periapical periodontitis is usually classified according to 
whether it is an acute/symptomatic process or a chronic/asymptomatic 
process. 
Acute periapical periodontitis, also termed acute
apical periodontitis, 
acute periradicular periodontitis, or symptomatic periapical periodontitis. 
Chronic periapical periodontitis, also termed chronic
apical periodontitis, 
chronic periradicular periodontitis, or assymptomatic periapical periodontitis. 
A periapical granuloma (also termed an apical granuloma or a radicular 
granuloma) is mass of chronically inflamed 
granulation tissue
that forms at
the apex of the 
root
of a 
nonvital
(dead) tooth. However, a periapical 
granuloma does not contain 
granulomatous inflammation
, and, therefore, is 

---

not a true 
granuloma
, but the term periapical granuloma is in common use 
(Wikipedia). 
A relatively high incidence of periodontitis and serious difficulties of its 
diagnosis and treatment is especially necessary to develop a common 
classification. Even the classification of periodontitis proposed in the XIX 
century was based mainly on clinical signs. In 1891, O. K. Limberg systematized 
clinical signs of inflammation of the periodontium and proposed a 
classification. 
In 1924, E. M. Gofung proposed a clinical and anatomical classification, 
which reflected localization and pathological changes
in case of periodontal 
inflammation. The author has divided the processes that occur in the 
periodontium
into
acute and chronic. 
I. Acute periodontitis. 
1. Acute marginal periodontitis. 
2. Acute apical periodontitis. 
3. Acute diffuse periodontitis.